Hahahahahahaha omg, I gamed grades all over the place in school. Learning the syllabus is like 20% of the work you do for an entire class. I would test homework assignments to see if the teachers would even read it and there were many times where I could completely hand in just a blank paper digitally and they mark me with a hundred.
In America at the very least grades are a complete joke that stems from an education system that prioritizes memorization and only includes deductive reasoning as an afterthought